{"cve":"CVE-2026-64121","nvd":{"published":"2026-07-19T16:17:53.663","modified":"2026-08-13T15:11:43.200","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ifb: report ethtool stats over num_tx_queues\n\nifb_dev_init() allocates dp->tx_private to dev->num_tx_queues\nentries via kzalloc_objs(*txp, dev->num_tx_queues). Both IFB\nper-queue RX and TX stats live in those entries: ifb_xmit() updates\ntxp->rx_stats using the skb queue mapping, ifb_ri_tasklet() updates\ntxp->tx_stats, and ifb_stats64() aggregates both over\ndev->num_tx_queues.\n\nThe ethtool stats callbacks instead size and walk the per-queue\nstats with dev->real_num_rx_queues and dev->real_num_tx_queues. With\nan asymmetric device where the RX queue count exceeds the TX queue\ncount, for example:\n\n    ip link add name ifb10 numtxqueues 1 numrxqueues 8 type ifb\n    ethtool -S ifb10\n\nifb_get_ethtool_stats() indexes past the tx_private allocation and\ncopies adjacent slab data through ETHTOOL_GSTATS.\n\nUse dev->num_tx_queues consistently for the stats strings, the\nstats count, and the stats data walks. This reports one RX stats\ngroup and one TX stats group for each backing ifb_q_private entry,\nwhich is the queue set IFB can actually populate.\n\nReproduced under UML+KASAN at v7.1-rc2:\n\n  BUG: KASAN: slab-out-of-bounds in ifb_fill_stats_data+0x3c/0xae\n  Read of size 8 at addr 0000000062dbd228 by task ethtool/36\n  ifb_fill_stats_data+0x3c/0xae\n  ifb_get_ethtool_stats+0xc0/0x129\n  __dev_ethtool+0x1ca5/0x363c\n  dev_ethtool+0x123/0x1b3\n  dev_ioctl+0x56c/0x744\n  sock_do_ioctl+0x15f/0x1b2\n  sock_ioctl+0x4d5/0x50a\n  sys_ioctl+0xd8b/0xde9\n\nWith the patch applied, the same UML+KASAN repro is silent and\nethtool -S ifb10 reports only the stats backed by the single\nallocated tx_private entry.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","score":7.1},"cwes":["CWE-125"],"references":["https://git.kernel.org/stable/c/16bd798cb6d8337d7c3eea1adc412f31b5181d5b","https://git.kernel.org/stable/c/2638e1773904d7aa8f24c6e7fda2ed7d69df6fa4","https://git.kernel.org/stable/c/301a554e458e2f5ec47f2c336a7cb03b877f9fd6","https://git.kernel.org/stable/c/5db89c99566fc4728cc92e941d8e1975711e24b5","https://git.kernel.org/stable/c/6afdb8113cb007f9332f59a9b7fd45731b8a9de5"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:45:36.895656543+00:00"},"epss":{"cve":"CVE-2026-64121","score":0.00126,"percentile":0.02246,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}